diff --git a/include/xo/reader2/DGlobalEnv.hpp b/include/xo/reader2/DGlobalEnv.hpp
index da7f8536..fa9d52f8 100644
--- a/include/xo/reader2/DGlobalEnv.hpp
+++ b/include/xo/reader2/DGlobalEnv.hpp
@@ -71,7 +71,7 @@ namespace xo {
             ///@{
 
             std::size_t shallow_size() const noexcept;
-            DGlobalEnv * shallow_copy(obj<AAllocator> mm) const noexcept;
+            DGlobalEnv * shallow_copy(obj<AAllocator> mm) noexcept;
             std::size_t forward_children(obj<ACollector> gc) noexcept;
 
             ///@}
diff --git a/include/xo/reader2/env/IGCObject_DGlobalEnv.hpp b/include/xo/reader2/env/IGCObject_DGlobalEnv.hpp
index a2fcb5f6..e4ff328a 100644
--- a/include/xo/reader2/env/IGCObject_DGlobalEnv.hpp
+++ b/include/xo/reader2/env/IGCObject_DGlobalEnv.hpp
@@ -52,10 +52,10 @@ namespace xo {
             // const methods
             /** memory consumption for this instance **/
             static size_type shallow_size(const DGlobalEnv & self) noexcept;
-            /** copy instance using allocator **/
-            static Opaque shallow_copy(const DGlobalEnv & self, obj<AAllocator> mm) noexcept;
 
             // non-const methods
+            /** copy instance using allocator **/
+            static Opaque shallow_copy(DGlobalEnv & self, obj<AAllocator> mm) noexcept;
             /** during GC: forward immdiate children **/
             static size_type forward_children(DGlobalEnv & self, obj<ACollector> gc) noexcept;
             ///@}
diff --git a/include/xo/reader2/parser/IGCObject_DSchematikaParser.hpp b/include/xo/reader2/parser/IGCObject_DSchematikaParser.hpp
index afe0d6b5..5c8e1975 100644
--- a/include/xo/reader2/parser/IGCObject_DSchematikaParser.hpp
+++ b/include/xo/reader2/parser/IGCObject_DSchematikaParser.hpp
@@ -52,10 +52,10 @@ namespace xo {
             // const methods
             /** memory consumption for this instance **/
             static size_type shallow_size(const DSchematikaParser & self) noexcept;
-            /** copy instance using allocator **/
-            static Opaque shallow_copy(const DSchematikaParser & self, obj<AAllocator> mm) noexcept;
 
             // non-const methods
+            /** copy instance using allocator **/
+            static Opaque shallow_copy(DSchematikaParser & self, obj<AAllocator> mm) noexcept;
             /** during GC: forward immdiate children **/
             static size_type forward_children(DSchematikaParser & self, obj<ACollector> gc) noexcept;
             ///@}
diff --git a/src/reader2/DGlobalEnv.cpp b/src/reader2/DGlobalEnv.cpp
index 386db966..c404d21a 100644
--- a/src/reader2/DGlobalEnv.cpp
+++ b/src/reader2/DGlobalEnv.cpp
@@ -114,7 +114,7 @@ namespace xo {
         }
 
         DGlobalEnv *
-        DGlobalEnv::shallow_copy(obj<AAllocator> mm) const noexcept
+        DGlobalEnv::shallow_copy(obj<AAllocator> mm) noexcept
         {
             return mm.std_copy_for<DGlobalEnv>(this);
         }
diff --git a/src/reader2/facet/IGCObject_DGlobalEnv.cpp b/src/reader2/facet/IGCObject_DGlobalEnv.cpp
index 76606d6f..9a3e3e45 100644
--- a/src/reader2/facet/IGCObject_DGlobalEnv.cpp
+++ b/src/reader2/facet/IGCObject_DGlobalEnv.cpp
@@ -22,11 +22,10 @@ namespace xo {
         }
 
         auto
-        IGCObject_DGlobalEnv::shallow_copy(const DGlobalEnv & self, obj<AAllocator> mm) noexcept -> Opaque
+        IGCObject_DGlobalEnv::shallow_copy(DGlobalEnv & self, obj<AAllocator> mm) noexcept -> Opaque
         {
             return self.shallow_copy(mm);
         }
-
         auto
         IGCObject_DGlobalEnv::forward_children(DGlobalEnv & self, obj<ACollector> gc) noexcept -> size_type
         {
diff --git a/src/reader2/facet/IGCObject_DSchematikaParser.cpp b/src/reader2/facet/IGCObject_DSchematikaParser.cpp
index 0ac80e37..582eb902 100644
--- a/src/reader2/facet/IGCObject_DSchematikaParser.cpp
+++ b/src/reader2/facet/IGCObject_DSchematikaParser.cpp
@@ -22,11 +22,10 @@ namespace xo {
         }
 
         auto
-        IGCObject_DSchematikaParser::shallow_copy(const DSchematikaParser & self, obj<AAllocator> mm) noexcept -> Opaque
+        IGCObject_DSchematikaParser::shallow_copy(DSchematikaParser & self, obj<AAllocator> mm) noexcept -> Opaque
         {
             return self.shallow_copy(mm);
         }
-
         auto
         IGCObject_DSchematikaParser::forward_children(DSchematikaParser & self, obj<ACollector> gc) noexcept -> size_type
         {